title: A single amino acid in the F2 subunit of respiratory syncytial virus fusion protein alters growth and fusogenicity.
abstract: Respiratory syncytial virus (RSV) causes severe lower respiratory tract infection in children, especially in infants less than 1 year of age. There are currently no licensed vaccines against RSV. rA2ΔM2-2 is a promising live-attenuated vaccine candidate that is currently being evaluated in the clinic. Attenuation of rA2ΔM2-2 is achieved by a single deletion of the M2-2 gene, which disrupts the balance between viral transcription and replication. Whilst performing a manufacturing feasibility study in a serum-free adapted Vero cell line, differences in growth kinetics and cytopathic effect (CPE) were identified between two rA2ΔM2-2 vaccine candidates. Comparative sequence analysis identified four amino acid differences between the two vaccine viruses. Recombinant rA2ΔM2-2 viruses carrying each of the four amino acid differences identified a K66E mutation in the F2 fragment of the fusion (F) protein as the cause of the growth and CPE differences. Syncytium-formation experiments with RSV F protein carrying mutations at aa 66 suggested that a change in charge at this residue within the F2 fragment can have a significant impact on fusion.
authors.affiliation: MedImmune, One MedImmune Way, Gaithersburg, MD 20878, USA.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Lawlor
authors.affiliation: MedImmune, One MedImmune Way, Gaithersburg, MD 20878, USA.
authors.forename: Jeanne H
authors.initials: JH
authors.lastname: Schickli
authors.affiliation: MedImmune, One MedImmune Way, Gaithersburg, MD 20878, USA.
authors.forename: Roderick S
authors.initials: RS
authors.lastname: Tang
mesh_terms: D000818:Animals; D002522:Chlorocebus aethiops; D003588:Cytopathogenic Effect, Viral; D015726:Giant Cells / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D009154:Mutation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D018357:Respiratory Syncytial Virus Infections / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D014709:Vero Cells; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D014760:Viral Fusion Proteins